As it is known in the art, a Wireless Local Area Network (WLAN) is a local-area network that uses high-frequency radio waves, rather than wires, to communicate between nodes. Various types of wireless LAN networks exist, and an example of a wireless data network is described in “IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements—Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, incorporated herein by reference (hereinafter “802.11”).
Each wireless network typically includes an Access Point device (AP) to allow one or more stations (STAs) to connect to a wired LAN. Access points transmit to the stations by selecting a frequency, or channel, in an available frequency spectrum for communication. 802.11(a) compliant devices operate in the 5 GHz frequency band using OFDM, with data rates up to 54 Mbps. 802.11(b) compliant devices operate in the 2.4 GHz frequency band using direct sequence spread spectrum, with data rates up to 11 Mbps. 802.11(b) devices currently represent the majority of installed wireless LANs. 802.11(g) compliant devices operate in the 2.4 GHz frequency band using OFDM, with data rates up to 54 Mbps.
Each AP device in a wireless network selects one channel within a defined frequency band of operation. However there may be interference in the frequency band generated by competing devices or resulting from physical or environmental characteristics at various points in the wireless network. It is desirable for an access point to efficiently identify the most desirable transmission channel.